Method of sterilization and apparatus therefor

ABSTRACT

A liquid germicide is measured; the measured liquid germicide is injected into hollows of concave articles ( 1 ); the more or less of volume of the liquid germicide is discriminated from the injected liquid germicide; only concave articles ( 1 ) which each have a proper volume of the liquid germicide attached thereto are stored into a storage ( 6 ); thereafter the storage is closed, and the concave articles are left to stand in the closed storage for a prescribed period of time. Since the liquid germicide is injected into the hollow of the concave article ( 1 ) after measuring, and the more or less of volume of volume of the solution is discriminated from the injected liquid germicide as described above, it is possible to attach a proper amount of liquid germicide to concave article ( 1 ) such as vessel or preform, and hence to accomplish efficient sterilization in the storage ( 6 ), without the risk of the defective sterilization.

TECHNICAL FIELD

The present invention relates to a method and a system for sterilizingvarious concave articles such as vessels made of various materialsincluding synthetic resins, paper and the like, and preforms for PET(polyethylene terephthalate) bottles.

BACKGROUND ART

It is the conventional practice to sterilize in advance the interior ofbottles and other vessels upon filling them with contents. PatentDocument 1 (JP2001-39414A) discloses sterilizing the interior of ablow-molded bottle by introducing mist of a sterilizing agent into thebottle. Patent Document 2 (JP2000-326935A) discloses sterilizing theinterior of a preform by dripping the preform into a germicidal solutionbefore blow molding.

SUMMARY OF INVENTION

According to the sterilizing process disclosed in Patent Document 1, themanufacturer of bottles (made of PET or the like) sterilizes blow-moldedbottles which are then transported to the user, and the user keeps thesebottles in a storage warehouse until contents are charged. In thesterilizing process disclosed in Patent Document 2, in contrast, themanufacture sterilizes the preforms each having a small volume inadvance of the blow molding thereof and conveys the sterilized preformsto the user, and the user keeps the preforms in a storage warehouseuntil contents are charged. The latter sterilizing method is thereforemore convenient in transportation and storage of the vessels. Therefore,the latter sterilizing process has been adopted recently in anincreasing number of cases than the former. In some cases where the bothmethods are used jointly, the sterilization is applied at the preformstage and further at the bottle stage. This practice provides anadvantage of reducing the amount of mist sprayed in the bottle.

The sterilizing process disclosed in Patent Document 2, while bringingabout many advantages in transportation and storage of vessels asdescribed above, has still room for further development in control ofthe volume and the concentration of the liquid germicide.

It is therefore an object of the present invention to provide a processand a system capable of more efficient sterilization as compared withthe conventional techniques.

To achieve the above mentioned object, the first aspect of the presentinvention provides a sterilizing process comprising the steps ofmeasuring a liquid germicide, injecting the measured liquid germicideinto hollows of concave articles (1), discriminating the more or less ofvolume of the liquid germicide from the injected liquid germicide,storing only the concave articles (1) which each have a proper volume ofthe liquid germicide into a storage (6), thereafter closing the storage(6), and leaving the concave articles to stand in the closed storage fora prescribed time period.

According to this first aspect of the present invention, the measuredliquid germicide is injected into hollows of the concave articles (1),and acceptability of volume is determined from the injected liquidgermicide. It is therefore possible to cause a proper volume of theliquid germicide to attach to the concave articles (1) such as vesselsor preforms, therefore, to sterilize efficiently the interior of articlewithin the storage (6), and to prevent the occurrence of incompletesterilization.

The second aspect of the present invention adopts, in the sterilizingprocess according to the first aspect, a sterilizing process furthercomprising the step of determining acceptability of the volume ofinjected liquid germicide by taking a photograph of the injected liquidgermicide.

According to the second aspect of the invention, in which the injectedliquid germicide is photographed, and acceptability of the volume ofinjected liquid germicide is determined from the photograph thus taken,the volume of injection can be accurately detected without disturbingthe injection of the liquid germicide.

The third aspect of the present invention adopts, in the sterilizingprocess according to the first or second aspect, a sterilizing processof injecting the liquid germicide toward a side wall of the innersurface of the concave article (1).

According to the third aspect of the invention, in which the liquidgermicide attaches to the inner side wall of the concave article (1) andfalls along the side wall, the liquid germicide attaches in so muchwider area of the hollow of the concave article, thus improving thesterilizing effect.

The fourth aspect of the present invention adopts a sterilizing systemcomprising a conveying means (7) which conveys concave article (1); aninjection means (8) which measures a liquid germicide and sprays it intoa hollow of the concave article (1) during the conveyance; a germicidefeeding means (12) which feeds the liquid germicide to the injectionmeans (8); a liquid volume discriminating means (9) which takes aphotograph of the liquid germicide ejected from the injection device (8)to determine acceptability of the liquid volume; and a storage (6) whichis to enclose the concave article (1) which has the liquid germicideattached therein.

According to the fourth aspect of the invention, it is possible toinject the liquid germicide fed from the germicide feeding means (12)into hollows of the concave articles (1) through the injection means (8)after measuring, so that the liquid germicide attaches with a constantvolume to every concave article (1) transported by the conveying means(7) continuously, and then to store the articles into the storage (6).Since acceptability of the liquid volume is determined by taking aphotograph of the liquid germicide after injection, it is possible tomore closely control the volume of adhering liquid germicide, and storeonly the concave articles (1) which each have a proper volume of theliquid germicide into the storage (6). This permits an efficientsterilization of a large number of concave articles (1), thuseliminating the risk of incomplete sterilization.

The fifth aspect of the present invention adopts, in the sterilizingsystem according to the fourth aspect of the invention, a sterilizingsystem in which, upon detection of unintended discharge of the liquidgermicide by the liquid volume discriminating means (9), the conveyanceof the concave article (1) by the conveying means (7) is suspended.

According to the fifth aspect of the invention, it is possible toprevent the concave articles (1) from receiving an excessive volume ofthe liquid germicide caused by the unintended discharge of the liquidgermicide, and to prevent the conveying line from contaminating with theliquid germicide.

The sixth aspect of the present invention adopts, in the sterilizingsystem according to the fourth aspect of the invention, a sterilizingsystem in which, upon detection of non-injection of the liquid germicideonto the concave article (1) by the liquid volume discriminating means(9), the concave article (1) is excluded from the conveying means (7).

According to the sixth aspect of the invention, the concave article (1)to which the liquid germicide has not been supplied and which would fallinto incomplete sterilization is excluded from the conveying means (7).The mixing of the incomplete sterilized concave article (1) in thestorage is prevented. Since the conveying means (7) continues to run,the sterilization operation can be sustained.

The seventh aspect of the present invention adopts, in the sterilizingsystem according to the fourth aspect of the invention, the sterilizingsystem is provided with a concentration determining means (28) fordetermining acceptability of concentration of the liquid germicide fedinto the injection means (8).

According to the seventh aspect of the invention, in which the liquidgermicide having the necessary concentration for sterilization can beinjected to the concave article (1) a proper sterilization can besustained.

The eighth aspect of the present invention adopts, in the sterilizingsystem according to the seventh aspect of the invention, a sterilizingsystem in which, upon detection of a defective concentration of theliquid germicide by the concentration determining means (28), theconveyance of the concave article (1) by the conveying means (7) issuspended.

According to the eighth aspect of the invention, large outbreaks of thedefectively sterilized concave articles (1) can be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1(A) is a vertical sectional view illustrating a preformsterilizable by the sterilizing process and system of the presentinvention; and FIG. 1(B) is a partially cutaway elevational view of abottle obtained by blow-molding this preform;

FIG. 2 is an elevational view schematically illustrating the sterilizingsystem of the present invention;

FIG. 3 is a plan view schematically illustrating the sterilizing systemof the present invention;

FIG. 4 is a block diagram illustrating a preparation apparatus of aliquid germicide;

FIG. 5 is a vertical sectional view of an injector;

FIG. 6 is a descriptive view of operation of the injector;

FIG. 7 is a descriptive view illustrating the positional relationshipbetween the injector and the preform;

FIG. 8 illustrates a monitor screen of a liquid volume discriminatingdevice; and

FIG. 9 is an elevational view illustrating another embodiment of theconveyor of the sterilizing system of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Now, some embodiments of the present invention will be described withreference to the drawings.

<First Embodiment>

In this embodiment, a preform 1 shown in FIG. 1(A) serves as a concavearticle which is an object of sterilization. According to thesterilizing process and system of the present invention, the object tobe sterilized is not limited to the preform 1, but a bottle 2 shown inFIG. 1(B) obtained by blow-molding the preform 1, and storages formedfrom various materials into various shapes are also included.

The preform 1 has a concave shape as a whole as shown in FIG. 1(A), andcomprises a lip part 3 having a male thread 3 a, a closed-bottomcylindrical barrel part 4 which is extended to the lip part 3, and aflange part 5 formed at the lower end of the lip part 3. The preform 1is integrally molded by the injection-molding of, for example,polyethylene terephthalate (PET). The injection-molded preform 1undergoes the injection of a liquid germicide as described later, andthen it is put in a storage, transported, and stored. Then, theclosed-bottom cylindrical barrel port 4 is blow-molded so as to shape abottle 2 having a larger volume as shown in FIG. 1(B). Next, the bottle2 is filled with contents, and is stamp-capped with a cap or the likenot shown.

The system for sterilizing the preform 1 has a configuration as shown inFIGS. 2 and 3, and it performs the functions of measuring a liquidgermicide; injecting the measured liquid germicide into hollows of thepreforms 1; discriminating the more or less of volume of the liquidgermicide from the injected liquid germicide; storing only the preforms1 which each have a proper volume of the liquid germicide adheringthereto into a container 6 as the storage; closing the container 6; andleaving the preforms to stand in the container for a prescribed timeperiod.

The liquid germicide to be used is, for example, an hydrogen peroxideaqueous solution diluted with a volatile solvent. The concentration ofhydrogen peroxide in the liquid germicide is adjusted to, for example, avalue within a range of from 0.1 to 10% by weight. Applicable solventsinclude ethyl alcohol, methyl alcohol, acetone, isopropyl alcohol andany mixed solvents prepared by mixing a plural kinds of solvents. Whilehydrogen peroxide aqueous solution can be singly used as the liquidgermicide, it is desirable to dilute it with the volatile solvent sothat the hydrogen peroxide aqueous solution can take the form of thinfilm which would be quickly spread over the inner surface of the preform1. Thus, the evaporation of hydrogen peroxide can be accelerated, andthe time required for sterilizing the inner surface of the concavepreform can be shortened.

Concretely, the sterilizing system comprises, as shown in FIGS. 2 and 3,a conveyor 7 which is a means for conveying the preform 1 as the concavearticle; an injector 8 which is a means for injecting the measuredliquid germicide into hollows of the preform 1 in conveyance; a liquidgermicide feeding apparatus 12 which is a means for feeding the liquidgermicide to the injector 8; a liquid volume discriminating device 9which is a means for determining acceptability of the liquid volume bytaking a photograph of the liquid germicide injected from the injector8; and a container 6 which encloses the preforms 1 having the liquidgermicide attached thereto.

The conveyor 7 has a plurality of turntables 7 a and 7 b. Each of theturntables 7 a and 7 b has clamps 10 for clamping a plurality ofpreforms 1 around the turntable at equal intervals so that theneighboring turntables 7 a and 7 b hand over the preforms 1 betweentheir clamps while rotating at the same peripheral speed. For example,an injection molding machine 11 is connected to the upstream-sideturntable 7 a via a feeding conveyor 7 c. The preforms 1injection-molded by the injection molding machine 11 are deliveredthrough the feeding conveyor 7 c to the clamps 10 of the turntable 7 a.When the injection molding machine 11 is located on a separate place,many injection-molded preforms 1 are transported by a container or thelike not shown to the entrance of the feeding conveyor 7 c, anddelivered through the feeding conveyor 7 c to the turntable 7 a. Thecontainer 6 as the storage is connected to the downstream-side turntable7 b via a discharge conveyor 7 d. The preforms 1 which take theinjection of the liquid germicide from the injector 8 while beingconveyed on the downstream-side turntable 7 b are discharged to thedischarge conveyor 7 d from the turntable 7 b. The discharge conveyor 7d throws the preforms 1 into the container 6. The turntables 7 a and 7 bare set to feed the preforms intermittently at regular intervals so asto effect an accurate delivery of preforms. However, continuous feed isalso possible.

The liquid germicide feeding apparatus 12 is equipped with a cushiontank 13. The cushion tank 13 is a tank elongated to the verticaldirection, to which an import pipe 14, circulation pipes 15 a and 15 b,a drainpipe 16 and the like for the liquid germicide are connected. Anupper-level sensor 17 a and a lower-level sensor 17 b are attached tothe inner side of the cushion tank 13, and the influent rate of theliquid germicide is controlled so that the liquid level 18 of the liquidgermicide is maintained between the upper and lower-level sensors 17 aand 17 b.

The import pipe 14 has an end extending from a liquid germicidereservoir tank 19 to the cushion tank 13 and the other end connected tothe circulation pipe 15 b. A feed pump 20, a filter 21, and valves 22and 23 are provided in the import pipe 14. The circulation pipes 15 aand 15 b are annularly connected to the cushion pipe 13. A circulationpump 24, various valves 25, 26 and 27, and a concentration meter 28 areprovided in the circulation pipes 15 a and 15 b, and a solvent reservoirtank 29, a drain pipe 30 and the like are connected thereto.

The concentration meter 28 is a device for measuring the concentrationof the liquid germicide, including a device such as a UV densitometerwhich determines the concentration of the liquid germicide by detectingthe ultraviolet rays quantity absorbed in the liquid germicide. Theapplicable concentration meter is not limited to the UV densitometer,but is also a densitometer of a type which causes absorption of visiblelight or infrared rays, or a densitometer of a type measuringconcentration by detecting the refracted light quantity.

A preparation equipment for the liquid germicide is annexed to theliquid germicide feeding apparatus 12. As shown in FIG. 4, thepreparation device 31 comprises a germicide reservoir tank 32 storinghydrogen peroxide solution, a germicide measuring tank 33 for measuringthe germicide, a solvent reservoir tank 34 which stores a volatilesolvent such as ethyl alcohol, a solvent measuring tank 35 whichmeasures the solvent, a mixing tank 36 where the germicide and thesolvent are mixed, a liquid germicide reservoir tank 19 which stores themixed liquid germicide, and a pipeline connecting these tanks. Variousvalves and pumps are arranged on the pipeline. Through control of thevarious valves and pumps, a predetermined volume of hydrogen peroxidesolution is sent from the germicide reservoir tank 32 to the mixing tank36 via the germicide measuring tank 33, and a predetermined volume ofsolvent is sent from the solvent reservoir tank 34 to the mixing tank 36via the solvent measuring tank 35. Hydrogen peroxide solution and thesolvent thus supplied are mixed in the mixing tank 36 to prepare theliquid germicide. The thus prepared liquid germicide is stored in theliquid germicide reservoir tank 19, and the liquid germicide reservoirtank 19 is conveyed to the proximity of the cushion tank 13.Alternatively, the liquid germicide reservoir tank 19 and the cushiontank 13 may directly be connected by piping.

The sterilizing process through this liquid germicide feeding apparatuswill be carried out as described below.

Prior to starting operation of the sterilizing system, the liquidgermicide exchange process in the sterilizing system is carried out inthe following procedure.

The valves of the cushion tank 13 and of drainpipes 16 of thecirculation pipes 15 a and 15 b are opened, and the liquid germicideused in the preceding operation is wholly discharged.

Then, the concentration meter 28 is set at the zero level while thevalve 26 from the solvent reservoir tank 29 is turned over, and thecirculation pump 24 is made to run so as to discharge the solvent fromthe valve 30.

Upon setting the concentration meter at the zero level, theconcentration of the liquid germicide is measured while the valve 26 isturned over so as to discharge the liquid germicide from the valve 30.If the concentration is out of the prescribed range, an alarm is soundedby a signal from the concentration meter 28. As a result, the exchangeprocess of the liquid germicide is stopped. The liquid germicide isprepared again, and the concentration meter 28 is set again at the zerolevel.

Upon confirmation of a normal concentration of the prepared liquidgermicide, the valves 16 and 30 are turned off, and the whole piping isfilled with the liquid germicide by operating the feed pump 20. The feedpump 20 is stopped at the moment when the liquid level 18 in the cushiontank 13 reaches the upper-level sensor 17 a.

This causes completion of the liquid germicide exchange process, makingthe sterilizing step operable.

At the start of the sterilizing step, the valve 23 is turned off, andthe liquid germicide in the cushion tank 13 is circulated by means ofthe circulation pump 24 through the circulation pipe 15 a, theconcentration meter 28, and the circulation pipe 15 b. The concentrationof the liquid germicide is always monitored by the concentration meter28 during the sterilizing step. When the concentration of the liquidgermicide comes to be out of the prescribed range, an alarm is soundedin response to the signal from the concentration meter 28. When anabnormal concentration is detected, the operation of the sterilizingsystem is stopped, and the liquid germicide is prepared again. Theconcentration meter 28 is set at the zero level again.

During the sterilizing step, when the liquid germicide is consumed andthe liquid level in the cushion tank 13 reaches the lower-level sensor17 b, the feed pump 20 is made to run so that the cushion tank 13 is fedwith the liquid germicide until the liquid level 18 reaches theupper-level sensor 17 a.

The injector 8 measures the liquid germicide in cooperation with thecushion tank 13. More specifically, as shown in FIGS. 2 and 3, theinjector 8 is connected to the cushion tank 13 through a conduit 37 forthe liquid germicide, and the injector 8 is charged with the liquidgermicide up to the same liquid level 18 as that of the liquid germicidein the cushion tank 13. A level gage 38 is equipped to the injector 8 soas to permit monitoring of the liquid level of the liquid germicide fromoutside the injector 8. In the figure shown, two injectors 8 is arrangedso as to face two preform 1 in the longitudinal direction on theturntable 7 a. Of course, it is possible that only one injector 8 may bearranged so as to face one preform 1, or three or more injectors may bearranged so as to face three or more preforms 1.

This injector 8 is an apparatus which measures the liquid germicidewhich is charged in the injector up to a certain volume at the sameliquid level as in the cushion tank 13, and ejects the liquid germicidein a certain direction, and which has a cylinder 39 having a nozzle 39 aat the leading end thereof, as shown in FIG. 5. A conduit 37 from thecushion tank 13 is connected to the cylinder 39, and an opening 39 b foroverflow is provided at a position above the connecting part of theconduit 37.

A pipe 39 c is provided to the overflow opening 39 b so as to preventthe overflowing liquid germicide from flowing along the outer wall ofthe cylinder 39 toward the preform 1.

A cylindrical measuring valve 40 which takes a prescribed volume ofliquid germicide in the cylinder 39, a plunger 41 slidable within themeasuring valve 40, and a needle valve 42 slidable along the center ofthe plunger 41 so as to face to the nozzle 39 a are provided in thecylinder 39. The measuring valve 40, the plunger 41 and the needle valve42 are individually driven by air cylinder devices which are not shownand use a working fluid such as air. Driving method is not limited tothat by the working fluid, but is also capable of using any methodsbased on a servo-motor or the like.

The injector 8 acts as shown in FIG. 6, and when a preform 1 is broughtto the position below the nozzle 39 a, the injector 8 ejects the liquidgermicide of a prescribed volume toward the opening of the cavity of thepreform. First, as shown in FIG. 5, the measuring valve 40 descendstoward the nozzle 39 a side in order to measure and capture the liquidgermicide of the prescribed volume (FIG. 6A); then, the needle valve 42ascends in order to open the nozzle 39 a (FIG. 6B); and the plunger 41comes down to cause ejection of the liquid germicide from the nozzle 39a in the direction of the arrow (FIG. 6C). Although the amount of theliquid germicide to be ejected can be varied by the volume, the innersurface area and the like of the preform 1, it may be, in general, aprescribed volume within the range from about 0.5 to 100 μ•. After theejection of the liquid germicide toward the preform 1, the needle valve42 descends to close the nozzle 39 a (FIG. 6D), and then the measuringvalve 40 ascends (FIG. 6E). Finally, the plunger 41 rises up (FIG. 6F)in order to be followed by the influent of the liquid germicide from thecushion tank 13 to the cylinder 39. These motions are repeated for eachpreform 1, and the liquid germicide in a measured amount is injectedinto the individual preforms 1.

The injection device of the liquid germicide is not limited to thatshown here, but is capable of using any other injecting method as far asthe injection device has an injecting rate capable of answering theproduction capacity of the line and keeps the injection volume stable.

The injector 8 may be arranged so that the axial center thereof is onthe extension of the axial center of the preform 1, but preferably bearranged so that the axial center is inclined relative to the preform 1on the conveyor 7 and the axial centers thus cross each other as shownin FIG. 7(A). As a result, the injected liquid germicide attaches to theinner surface of the barrel part 4 or lip part 3 which are the sidewallof the preform 1 and falls along the inner surface of the side wall. Theliquid germicide attaches to so much larger area of the cavity in thepreform, i.e., the concave article, which is followed by leading to animproved sterilizing effect.

The liquid volume discriminating device 9 serves to determineacceptability of the injection volume by taking a photograph of theliquid germicide ejected from the injector 8. As shown in FIGS. 2 and 3,the device is provided with a lamp 43 illuminating the liquid germicidedischarged from the nozzle 39 a of the injector 8, and a camera 44taking a photograph of the discharged liquid germicide.

The camera 44 is for example a CCD camera, and takes a photograph of theliquid germicide illuminated by the lamp 43. The image taken by thecamera 44 is displayed on a monitor 46 via an image controller 45. Asshown in FIG. 8(A), an image 39 b of the nozzle 39 a of the injector 8,an image 47 of the liquid germicide ejected linearly from the nozzle 39a, and an image 3 b of the lip part 3 of the preform 1 are displayed onthe screen 46 a of the monitor 46.

The liquid volume discriminating device 9 cuts off the portion of theimage 47 for the liquid germicide by a window 48, and determines thepresence or absence of the liquid germicide at a timing when the preform1 becomes directly below the injector 8. If the absence of the liquidgermicide is detected at the timing, the device 9 issues a signal toannounce the occurrence of defective sterilization. The liquid volumediscriminating device 9 counts the number of pixels in the image 47 ofthe liquid germicide within the window 48. If the counted number islarger or smaller than a prescribed number of pixels set in advance, thedevice issues a signal of defective sterilization.

As shown in FIG. 3, a rejecter 49 for removing thedefectively-sterilized preform 1 is provided on the turntable 7 b. Uponreceipt of a signal of defective sterilization, the rejecter 49 takesthe corresponding preforms 1 away from the turntable 7 b. The shownrejector 49 is an equipment of the type which widens the clamp 10 on theturntable 7 b in order to allow the preform 1 to fall down under theturntable 7 b. The rejector 49 may be the type of blowing off thepreform 1 by air-blow, or the type of disengaging a trap plate which isused for supporting the preform 1.

When the liquid volume discriminating device 9 detects the presence ofan image 47 of the liquid germicide at a timing other than the timingfor conveying the concave preform 1 by the turntables 7 a and 7 b as theconveying means 7, the liquid volume discriminating device 9 deems it asrepresenting a state of unintended discharge of the liquid germicide,and issues a signal for suspending the work of the turntables 7 a and 7b. More specifically, as shown in FIG. 8(B), when the image 47 of theliquid germicide is detected between a preform 1 and the followingpreform 1 being conveyed, the liquid volume discriminating device 9deems it as representing occurrence of unintended discharge of theliquid germicide from the injector 8, and issues a conveyance stoppingsignal. This can bring the feeding state of the liquid germiciderehabilitating. Therefore, it is possible to prevent the concavearticles 1 from receiving an excessive volume of the liquid germicide,and to prevent the conveying line from contaminating with the liquidgermicide.

When the number of pixels of the image 47 of the liquid germicidecounted at a timing for conveying the preform 1 as the concave articleby the turntables 7 a and 7 b as the conveying means 7 is detected asbeing out of the prescribed range, the liquid volume discriminatingdevice 9 deems it as suggesting the fact that the liquid germicide hasnot been injected, and issues a signal of defective sterilization. Therejector 49 excludes the corresponding preforms 1 from the turntable 7b, while the turntables 7 a and 7 b continue to drive. As a result, itis possible to prevent the defectively sterilized preforms from storingin the storage together with the successfully sterilized preforms.

The storage may take the form, for example, of a lidded container 6, andthe preforms 1 which each have the liquid germicide attached thereto ina proper amount with a proper concentration, and which are dischargedfrom the discharge conveyor 7 d are thrown into the container 6. Thecontainer 6 is equipped therein with a bag made of a synthetic resin andbeing in the inflated state, and the preforms 1 are thrown into the bag.When a prescribed number of preforms 1 accumulate in the bag, the bag isclosed and conveyed out, together with the container 6, from thesterilizing system. The closed container 6 is subsequently transportedand stored. In the meantime, the liquid germicide is evaporated in eachpreform in the bag in the container 6 to sterilize the interior of thepreforms 1. The container is opened after aging as described above.Sterilized preforms 1 are taken out from the bag in the container 6,sent to the blow molding machine (not shown), and molded into bottles 2.The storage may be the container 6 or a box used singly, or may be a bagused singly so far as it is possible to close the opening thereof. Asthe method of closing, any various method is acceptable. The variousmethods include folding the lip part of the bag, heat-sealing the bag,and nipping the bag with a clip.

The operation of the sterilizing system having the above-mentionedconfiguration will now be described.

The preforms 1 injection-molded by the injection molding machine 11 arefed from the feeding conveyor 7 c to the turntable 7 b on the downstreamside via the turntable 7 a on the upstream side. The turntable 7 bsuccessively receives the preforms 1 while rotating, and conveys thesame directly below the injector 8.

The liquid germicide having a prescribed concentration is fed from thegermicide feeding apparatus 12 via the cushion tank 13 into the cylinder39 of the injector 8. The liquid germicide is obtained by mixinghydrogen peroxide solution and a volatile solvent with a prescribedratio in a preparation device 31. The concentration of the liquidgermicide is continuously monitored with the concentration meter 28 inthe germicide feeding apparatus 12, which results in the successivefeeding of the liquid germicide with a constant concentration to theinjector 8.

In the cushion tank 13, the liquid germicide is constantly kept at theprescribed liquid level 18, and the same liquid level of liquidgermicide as in the cushion tank 13 is stored in the cylinder 39 of theinjector 8. The injector 8 takes in the liquid germicide of theprescribed volume by means of the measuring valve 40 in the cylinder 39.Upon arrival of the preform 1 under the nozzle 39 a, the injector 8activates the needle valve 42 to open the nozzle 39 a, and activates theplunger 41 to eject the liquid germicide from the nozzle 39 a.

The liquid germicide ejected from the nozzle 39 a of the injector 8,which is in a linear shape, is quickly introduced into the cavity of thepreform 1. The liquid germicide attaches to the inner surface of theside wall of the preform 1, then falls along the side wall, and thusattaches to a wide range in the cavity of the preform 1.

The liquid volume discriminating device 9 determines acceptability ofthe injection volume by taking a photograph of the liquid germicideejected from the injector 8. The image taken by the camera 44 isdisplayed on a monitor 46 via an image controller 45.

The liquid volume discriminating device 9 cuts off the portion of theimage 47 for the liquid germicide on the screen of the monitor 46 by awindow 48, and determines the presence or absence of the liquidgermicide at a timing when the preform 1 becomes directly below theinjector 8. If the absence of the liquid germicide is detected at thetiming, the liquid volume discriminating device 9 issues a signal ofdefective sterilization.

The liquid volume discriminating device 9 counts the number of pixels inan image of the liquid germicide within the window 48. If the countednumber is larger or smaller than a prescribed number of pixels set inadvance, the device issues a signal of defective sterilization.

The preform 1 which is judged as being defectively sterilized by theliquid volume discriminating device 9 is removed from the turntable 7 bwhen the preform 1 is conveyed by the turntable 7 b to the rejector 49.

When the liquid volume discriminating device 9 detects the presence ofan image 47 of the liquid germicide at a timing other than the timingfor conveying the concave preform 1 by the turntables 7 b, the liquidvolume discriminating device 9 deems it as representing a state ofunintended discharge of the liquid germicide, and issues a signal forsuspending the work of the turntables 7 a and 7 b. Therefore, it ispossible to prevent the preforms 1 and the conveying line fromcontaminating with the liquid germicide.

Further, the concentration of the liquid germicide is successivelymonitored by the concentration meter 28 throughout the operation of thesterilizing system. When the concentration of the liquid germicide comesto be out of the prescribed range, an alarm is sounded in response tothe signal from the concentration meter 28. When an abnormalconcentration is detected, the operation of the sterilizing system isstopped, and the liquid germicide is prepared again in order to resumethe sterilizing treatment.

The preforms 1 to which the liquid germicide has been injected at aproper concentration and a proper amount are thrown into the bag in thecontainer 6 via the downstream turntable 7 b and the discharge conveyor7 d.

When the preforms 1 are accumulated in a prescribed amount in thecontainer 6, the bag in the container is closed, and the container 6 isconveyed out from the sterilizing system.

Subsequently, the container 6 is transported to the user of the preformsor the others, and stored at there. During this transportation andstorage, in the bag of the container 6, the liquid germicide evaporatesin each preform 1, and vapor of hydrogen peroxide sterilizes theinterior of the preform 1. After the completion of such aging ofsterilization, the bag in the container is opened, and the sterilizedpreforms are taken out from the container 6.

The sterilized preform 1 is molded into a bottle 2 by a blow moldingmachine, and the obtained bottle is filled with the contents under anaseptic atmosphere, given a cap, and delivered as a product.

<Second Embodiment>

In this second embodiment, as shown in FIG. 9, a screw conveyor 50 isused as conveying means, while the turntables 7 a and 7 b are used inthe first embodiment. The screw conveyor 50 comprises a pair of screwsarranged in parallel, and conveys the preform 1 by holding the barrel 4of the preform 1 between the screws. A pair of guide rails 51 which arein parallel with each other and in contact with the flange section 5 ofthe preform 1 are provided above the screws.

Further, the injector 8 is set above the screw conveyor 50, and which isarranged in the direction of shown in FIG. 7(B). The liquid germicide isejected from the injector 8 toward the preform 1. While the preform 1 isinclined on the screw conveyor 50, the injector 8 is verticallyarranged. As a result, the liquid germicide is injected toward the innersurface of the side wall of the preform 1 as shown in FIG. 7(B).

1. A sterilizing process comprising the steps of measuring a liquidgermicide; injecting said measured liquid germicide into hollows ofconcave articles; discriminating the more or less of volume of theliquid germicide from the injected liquid germicide; storing only theconcave articles which each have a proper volume of the liquid germicideinto a storage, then closing the storage, and leaving the concavearticles to stand in the closed storage for a prescribed time period. 2.The sterilizing process according to claim 1, wherein acceptability ofthe volume of injected liquid germicide is determined by taking aphotograph of the injected liquid germicide.
 3. The sterilizing processaccording to claim 1 or 2, wherein said liquid germicide is injectedtoward a side wall of the concave article.
 4. A sterilizing systemcomprising conveying means which conveys concave article; an injectionmeans which measures a liquid germicide and sprays it into a hollow ofthe concave article during the conveyance; a germicide feeding meanswhich feeds the liquid germicide to the injection means; a liquid volumediscriminating means which takes a photograph of the liquid germicideejected from the injection device to determine acceptability of theliquid volume; and a storage which is to enclose the concave articlewhich has the liquid germicide attached therein.
 5. The sterilizingsystem according to claim 4, wherein, upon detection of unintendeddischarge of the liquid germicide by the liquid volume discriminatingmeans, the conveyance of the concave article by the conveying means issuspended.
 6. The sterilizing system according to claim 4, wherein, upondetection of non-injection of the liquid germicide onto the concavearticle by the liquid volume discriminating means, said concave articleis excluded from the conveying means.
 7. The sterilizing systemaccording to claim 4, wherein said system is provided with aconcentration determining means which determines acceptability ofconcentration of the liquid germicide fed into the injection means. 8.The sterilizing system according to claim 7, wherein, upon detection ofa defective concentration of the liquid germicide by the concentrationdetermining means, the conveyance of the concave article by theconveying means is suspended.